<span>An equation that is satisfied for every value of the variable for which both sides are defined is called an identity.
For example:
Given the equation
3x + 4 = x + 2(x + 2)
Notice that for any value of x you use, the equation is true.
Thus, this type of equation is called an identity.
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20% of 65 = 65 * 1/5, which is 13. so 20% of 65 is $13. so a discount of 20% = 65-13 which is $52
8x+4 would be the answer if you combine like terms
Given that ∠B ≅ ∠C.
to prove that the sides AB = AC
This can be done by the method of contradiction.
If possible let AB
=AC
Then either AB>AC or AB<AC
Case i: If AB>AC, then by triangle axiom, Angle C > angle B.
But since angle C = angle B, we get AB cannot be greater than AC
Case ii: If AB<AC, then by triangle axiom, Angle C < angle B.
But since angle C = angle B, we get AB cannot be less than AC
Conclusion:
Since AB cannot be greater than AC nor less than AC, we have only one possibility. that is AB =AC
Hence if angle B = angle C it follows that
AB = AC, and AB ≅ AC.